Known fault location methods use the lumped parameter line model to approximate power networks for analysis. The lumped parameter line model approximates the parameters of the circuit into ideal components such as resistors, capacitors, and inductors. The lumped parameter line model does not represent a real circuit in which the parameters are distributed uniformly through the length of the line. For example, given the per kilometer (km) impedance (z), admittance (y), and line length (l) in km, the equivalent series impedance for the entire line length under the lumped parameter line model is zl. In contrast, the equivalent series impedance for the entire line length under the distributed parameter line model is √{square root over (z/y)} sinh(√{square root over (zyl)}).
Further, most known fault location methods for power transmission lines ignore mutual coupling between parallel lines as well as the charging effect of the shunt capacitances of the lines. Additionally, some known fault location methods require source impedances at the two terminal substations and assume constant source impedances, so that these methods are adversely impacted by the varying source impedance.
Utilizing the lumped parameter line model and/or ignoring shunt capacitance causes the accuracy of the fault location algorithm to decrease as the length of the power transmission line increases. Thus, while known fault location methods may be useful for shorter distance transmission lines, there is room for improvement in the accuracy of fault location methods for longer distance power transmission lines.